Ricoh B079, Service Manual

Page: 834 / 948

VIDEO DATA PATH
B547 126 SM
Memory Transmission and Parallel Memory Transmission
The base copier's scanner scans the original at the selected resolution in inch
format. The BiCU processes the data and transfers it to the FCU.
When scanning a fax original, the BiCU uses the MTF, independent dot erase and
thresholding parameter settings programmed in the fax unit’s scanner bit
switches, not the copier's SP modes.
Then, the FCU converts the data to mm format, and compresses the data in MMR
or raw format to store it in the SAF memory. If image rotation will be done, the
image is rotated in page memory before compression.
At the time of transmission, the FCU decompresses the stored data, then re-
compresses and/or reduces the data if necessary for transmission. Either the NCU
or SiG4 (optional) transmits the data to the line.
Immediate Transmission
The base copier's scanner scans the original at the resolution agreed with the
receiving terminal. The BiCU video processes the data and transfers it to the FCU.
When scanning a fax original, the BiCU uses the MTF, independent dot erase and
thresholding parameter settings programmed in the fax unit’s scanner bit
switches, not the copier's SP modes.
Then the FCU stores the data in page memory, and compresses the data for
transmission. Either the NCU or SiG4 (optional) transmits the data to the line.
JBIG Transmission
•
Memory transmission: If the receiver has JBIG compression, the data goes
from the DCR to the QM-Coder on the Function Upgrade Unit for JBIG
compression. Then either the NCU or SiG4 (ISDN G3) transmits the data to the
line. When an optional G3 unit (SG3) is installed and PSTN2 is selected as the
line type, JBIG compression is available, but only for the PSTN-2 line.
•
Immediate transmission: If the receiver has JBIG compression, the data goes
from the page memory to the QM-Coder on the Function Upgrade Unit for JBIG
compression. Then either the NCU or SiG4 (ISDN G3) transmits the data to the
line. When an optional G3 unit (SG3) is installed and PSTN2 is selected as the
line type, JBIG compression is available, but only for the PSTN-2 line.
I-G3 (ISDN G3) Transmission
G3 transmission is available through the ISDN line by using the optional G4 unit
(SiG4). In this case, the G3 modem is used for the I-G3 transmission. When an
optional G3 unit (SG3) is installed, the modem on the SG3 can be also used for the
I-G3 transmission. This means that two I-G3 transmission is available at the same
time.